The present invention relates to a clamping device for objects, for example for workpieces to be treated.
One of such clamping devices is disclosed in the patent document EP 800 884 82. It is believed that the existing clamping device can be further improved.
Accordingly, it is an object of present invention to provide a clamping device for objects, for example for workpieces to be treated which is designed simply and cost-favorably, and is suitable both for outer clamping and an inner clamping.
In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a clamping device for objects, which has a housing, at least two clamping jaws which is radially displaceably guided relative to a longitudinal central axis; actuating element associated with said clamping jaws for actuating the latter; clamping pistons displaceable in a cylinder chamber and acted for clamping of said clamping jaws by a pressure medium under pressure at least in one working direction, said actuating element being in operative communication with said clamping piston at least in a working position; at least one central adjusting device displaceably arranged in said housing and acting on said actuating elements; abutment means including an abutment for each of said actuating element against which each of said actuating elements can abut, said actuating elements being formed as angular levers which is turnably held in said housing and engage at one end with associated one of said clamping pistons and on the other hand with an associated one of said clamping jaws.
When the clamping device is designed in accordance with the present invention, it is suitable both for outer clamping and simultaneously also for inner clamping. With a corresponding arrangement of outer clamping surfaces and inner clamping surfaces on the clamping jaws, it can be used as an outer and inner clamping device equally. The clamping device requires only a few components which are suitable both for the outer clamping device and the inner clamping device, so that the number of components is reduced. It has an additional advantage that the clamping device is designed as a centering and in particular hydraulically equalizing jaw chuck. It can have at least one tool clamping jaw and depending on the design can include more clamping jaws, for example three clamping jaws or four, six, eight, ten, twelve, or depending on the conditions also an odd number of clamping jaws.
The clamping device has the advantage that at least during performing of a clamping process, several clamping jaws or all clamping jaws gently lie on the object to be clamped with accompanying automatic centering, before a uniform clamping force is applied by the clamping jaws. The clamping jaws in a known manner can be single-component or two-component or multi-component jaws. When needed, also swinging jaws can be used, in which the number of force applying points is doubled, which can lead to fine clamping of the objects to be clamped. During clamping also with an asymmetrical outlet position, the clamping forces are applied symmetrically so that the object is clamped uniformly. The clamping device is compact and space-consuming and allows a flat construction.
It is also advantageous that with the clamping device of the invention, the clamping forces are transmitted and also long clamping paths can be covered. It is a further advantageous that due to the lever arrangement of the individual elements, a force application is provided and at least partially by lever action a centrifugal force equalization is obtained.
Depending on the clamping objectives, the clamping device has at least two clamping jaws. When needed, also four or more clamping jaws can be provided, with the advantage that an odd number of clamping jaws is used, which is not however completely necessary. Since the clamping device in the output position is loaded with an opening force, against which it is necessary for work for transfer to the clamping position, it is guaranteed that in the output condition all clamping jaws are in the same output position.
During contacting the object which is clamped and resulting centering, a force which is only insignificantly greater than the opening force is required, whereby the clamping jaws abut relatively tight against the object to be clamped before, by the acting on the clamping piston, a uniform clamping force is applied by the clamping jaws to the object.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.